Starting with version 0.65, DOSBox allows you to create movies out of screen
output.

To record a movie, you have to press CTRL-ALT-F5.
To stop/end the recording, you have to press CTRL-ALT-F5 again.

To play the recorded movie, you need a movie player which can handle the
ZMBV codec. MS Windows users can find this codec in the start menu entry of
DOSBox.
-StartmenÃ¼\Programme\DOSBox-0.72\Video\Install movie codec
or
-x:\Programme\DOSBox-0.72\zmbv\zmbv.inf

Users of Linux and other OSes should look for a movie player that
uses the ffmpeg libary (you may need to update or ask your distribution to
upgrade).